U.S. Pat. No. 4,319,903 discloses apparatus for preheating glass batch material before it is fed to a glass batch melting furnace. Heating media heated by exhaust gases from the furnace are fed one way through a rotating drum and glass batch material is fed the opposite way. The purpose of the preheating apparatus is to essentially double the rate at which molten glass can be withdrawn from the furnace. At the inlet end of the drum for the heating media, an inlet conduit passes through a central opening in an end plate of the drum and is provided with a stationary sealing flange inside the drum, the sealing flange holding a wear plate in contact with the inner side of the rotating end plate of the drum. Glass batch material works its way between the wear plate and the drum end plate. At temperatures higher than about 1000.degree. F., this trapped glass batch material partially fuses and tends to bind the wear plate and end plate together, necessitating shutdown of the drum, temporary bypassing of the preheater, upsetting of the equilibrium of the furnace from the feeding of cold batch material thereto, and reducing the rate at which molten glass can be withdrawn from the furnace. The same harmful results occur when the wear plate needs replacement.